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Many spectral lines are very sensitive to the surface gravity of the star - which enables a distinction between dwarfs and giants, because a giant's surface gravity is factors of $\sim 100$ lower than that of a dwarf of the same temperature. The reason that surface gravity plays a role is via hydrostatic equilibrium; the densities and pressures in a gas ...


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The Oort cloud is a theoretical object. Its existence is more or less accepted on the basis of "comets have to come from somewhere", but no Oort cloud object has ever been observed (except for some comets that pass near us that presumably came from the cloud). It is theorized that it has two components, one disky and one spherical, both centered on the Solar ...


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If the Oort cloud is included to the Solar System and the calculation, it has a potential to influence the barycenter significantly. The distance of the Oort cloud from the Sun is some 100,000 AU (plus minus a factor of two) and its total mass is around 5 times the Earth's mass. If there were a single orbiting object at the location of the Oort cloud, its ...


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What are the possible measurement error barycenter of the Solar System in NASA data? The barycenter cannot be directly observed. It is instead a computed quantity. The location of the barycenter would be easily determined if the universe was cartesian (it isn't), if we could simultaneously observe the locations of all of the objects in the solar system ...



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